title: Crystal structure, SAXS and kinetic mechanism of hyperthermophilic ADP-dependent glucokinase from Thermococcus litoralis reveal a conserved mechanism for catalysis.
abstract: ADP-dependent glucokinases represent a unique family of kinases that belong to the ribokinase superfamily, being present mainly in hyperthermophilic archaea. For these enzymes there is no agreement about the magnitude of the structural transitions associated with ligand binding and whether they are meaningful to the function of the enzyme. We used the ADP-dependent glucokinase from Thermococcus litoralis as a model to investigate the conformational changes observed in X-ray crystallographic structures upon substrate binding and to compare them with those determined in solution in order to understand their interplay with the glucokinase function. Initial velocity studies indicate that catalysis follows a sequential ordered mechanism that correlates with the structural transitions experienced by the enzyme in solution and in the crystal state. The combined data allowed us to resolve the open-closed conformational transition that accounts for the complete reaction cycle and to identify the corresponding clusters of aminoacids residues responsible for it. These results provide molecular bases for a general mechanism conserved across the ADP-dependent kinase family.
authors.affiliation: Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile.
authors.forename: Jaime Andrés
authors.initials: JA
authors.lastname: Rivas-Pardo
authors.forename: Alejandra
authors.initials: A
authors.lastname: Herrera-Morande
authors.forename: Victor
authors.initials: V
authors.lastname: Castro-Fernandez
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Fernandez
authors.forename: M Cristina
authors.initials: MC
authors.lastname: Vega
authors.forename: Victoria
authors.initials: V
authors.lastname: Guixé
mesh_terms: D000255:Adenosine Triphosphate / Q000737:chemistry / Q000378:metabolism; D000595:Amino Acid Sequence; D019843:Archaeal Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D001665:Binding Sites / Q000235:genetics; D055162:Biocatalysis; D018360:Crystallography, X-Ray; D005941:Glucokinase / Q000737:chemistry* / Q000145:classification / Q000378:metabolism; D005947:Glucose / Q000737:chemistry / Q000378:metabolism; D006358:Hot Temperature; D007700:Kinetics; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010802:Phylogeny; D011485:Protein Binding; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D053838:Scattering, Small Angle; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity; D019712:Thermococcus / Q000201:enzymology* / Q000235:genetics; D014961:X-Ray Diffraction
chemical_list: D019843:Archaeal Proteins; D000255:Adenosine Triphosphate; C420842:ADP-dependent glucokinase; D005941:Glucokinase; D005947:Glucose